Showing papers in "Developmental and Comparative Immunology in 1997"
TL;DR: While chronic stress is eventually immunosuppressive, acute stress/trauma may help enhance both cellular and humoral components of innate defenses at times of likely need.
Abstract: The fight-or-flight response prepares an animal for coping with alarming situations and their potential consequences, which include injury. The possible involvement of innate components of immunity in the response has received little attention. We determined plasma concentrations of stress hormones and lysozyme activity before and after a 10 min handling stressor. Rainbow trout (Oncorhynchus mykiss) were anesthetized in their home tanks, bled, revived, and then stressed by being held in the air in a net for 30 s and placed in a shallow bucket of water for 10 min. Fish were then captured, concussed (in one of two experiments) and bled again. Control fish were also bled twice, but were kept anesthetized in their holding tanks between bleedings. Following the stressor, plasma cortisol, adrenaline and lysozyme activity were significantly increased. The experiment was repeated 4 months later with a similar outcome. While chronic stress is eventually immunosuppressive, acute stress/trauma may help enhance both cellular and humoral components of innate defenses at times of likely need.
423 citations
TL;DR: Serum can be used as an alternative for the study of the shrimp proPO activating system, as it is much more readily obtained than HLS, and its involvement in non-self recognition is suggested.
Abstract: In the present study we investigated the proPO activating system of the penaeid Penaeus paulensis, focusing on its role in the shrimp immune system. The great majority of PO activity (more than 90%) was found in the shrimp hemocytes. The enzyme activity was greatly enhanced by components of microorganism cell walls, such as LPS and beta-1,3-glucans, suggesting its involvement in non-self recognition. PO activity was also found in the shrimp serum and trypsin, and LPS were able to increase the enzyme activity. Thus, serum can be used as an alternative for the study of the shrimp proPO activating system, as it is much more readily obtained than HLS. PO activity was cation-dependent, and 5 mM of calcium and 10 mM of magnesium were the optimal concentrations for the enzyme activity. An immune factor was found in the shrimp HLS, capable of inducing cell-adhesion and degranulation of the penaeid hemocytes.
194 citations
TL;DR: The features of T cell replicative senescence are described, several possible mechanisms for the generation of senescent T cells in vivo are presented, and it is proposed that replicativesenescence may explain immune exhaustion.
Abstract: The CD28 molecule, a disulfide-linked homodimer expressed on peripheral T cells and thymocytes, mediates an essential costimulatory signal following engagement of the T cell receptor (TCR). Increased proportions of CD28 — T cells have been observed during aging and in situations of chronic immune stimulation, but the origin and functional characteristics of these cells have been unclear. T cells which reach replicative senescence in culture after multiple rounds of cell division have shortened telomeres, respond poorly to stress stimuli, and no longer express CD28, suggesting that CD28 — T cells observed in vivo may be the progeny of memory cells which have been repeatedly stimulated. This review describes the features of Tcell replicative senescence, presents several possible mechanisms for the generation of senescent T cells in vivo, and proposes that replicative senescence may explain immune exhaustion.
168 citations
TL;DR: Mx proteins are induced by type I interferons in mice and humans and inhibit the replication of several negative-stranded RNA viruses, and in this work Mx genes in Atlantic salmon were studied using the double stranded RNA, polyinosinic: polycytidylic acid (poly I:C), to induce interferon production.
Abstract: Mx proteins are induced by type I interferons in mice and humans and inhibit the replication of several negative-stranded RNA viruses. In this work Mx genes in Atlantic salmon were studied using the double stranded RNA, polyinosinic: polycytidylic acid (poly I:C), to induce interferon production. Northern blot analysis showed Mx mRNA in liver, head kidney and gills 2 days after poly I:C injection of fish, but not in untreated fish or fish injected with saline or LPS. Mx transcripts of 2.4 and 1.9 kb were detected in the liver. By screening of a cDNA library, three different full length Mx cDNA clones, ASMx1, ASMx2 and ASMx3, were identified and sequenced. The deduced ASMx proteins all contain 623 amino acids and show the tripartite GTP-binding motif typical of vertebrate Mx proteins. ASMx1 and ASMx2 may represent alleles of the same gene whereas ASMx3 represents a different gene. The deduced ASMx proteins showed 96 to 98% sequence identity with rainbow trout Mx1 and Mx3 and about 88% identity with rainbow trout Mx2 protein.
136 citations
TL;DR: This study demonstrates the selective response of plasma and haemocytic proPO to activation by different types of bacterial LPS tested and suggests that proPO system in both plasma andHaemocytes of P. viridis serves an important function in non-self recognition and host immune reactions.
Abstract: Phenoloxidase activity was detected in plasma and haemocytes of the marine mussel Perna viridis. This enzyme exists as a proenzyme, prophenoloxidase (proPO), in both these haemolymph fractions and could be activated in vitro by exogenous proteases (trypsin and alpha-chymotrypsin) and a detergent (sodium dodecyl sulphate). In addition, laminarin (a polymer of beta-1,3 glucan) and bacterial lipopolysaccharides (LPSa) effectively triggered proPO activation in these haemolymph fractions. The activation of proPO by non-self molecules was dependent upon calcium ions at a low concentration. This activation process appeared to involve a limited proteolysis, since serine protease inhibitors (soybean trypsin inhibitor, benzamidine or p-nitrophenyl-p'-guanidinobenzoate) suppressed conversion of proPO to the active enzyme. This study demonstrates the selective response of plasma and haemocytic proPO to activation by different types of bacterial LPS tested and suggests that proPO system in both plasma and haemocytes of P. viridis serves an important function in non-self recognition and host immune reactions.
127 citations
TL;DR: The pathogenesis of osteoporosis in the context of aging and IL-6 is discussed and murine models suggest that IL- 6 plays a central role in bone resorption.
Abstract: Osteoporosis is a major cause of morbidity in older people. There are a large number of risk factors for the development of osteoporosis. However, these risk factors eventually must mediate their effects through modulation of bone remodeling. A variety of compounds including hormones and mutrients modulate bone remodeling. In addition to these well-characterized substances, the immune system plays a role in bone remodeling through pro-inflammatory cytokines. Specifically, interleukin-1 (IL-1), IL-11, interferon-g are known to influence osteoclasts and osteoblasts. Recently, the cytokine IL-6 has joined ranks with these cytokines as a bone reactive agent. IL-6 has been shown to increase with age and menopause. Additionally, murine models suggest that IL-6 plays a central role in bone resorption. Finally, in vitro studies demonstrate that IL-6 induces osteoclast activity. In this review, we will discuss the pathogenesis of osteoporosis in the context of aging and IL-6.
77 citations
TL;DR: Southern blot analyses using an exon three probe revealed two to four hybridizing fragments with considerable restriction fragment length polymorphisms evident among randomly selected outbred channel catfish, consistent with the presence of at least two functional polymorphic MHC class II A gene loci.
Abstract: In order to characterize the Major histocompatibility complex (MHC) class II A genes of the channel catfish (Ictalurus punctatus) a cDNA library was screened and PCR was performed. Four different full-length cDNA sequences for MHC class II A genes were obtained from a clonal B cell line derived from an outbred fish. Two different genomic sequences and corresponding cDNAs were obtained from a presumably homozygous gynogenetic catfish. The A genes have five exons and four phase one introns. The first exon encodes the 5′ untranslated region (UTR) and leader peptide; the second and third exons encode the α1 and α2 domains, respectively. The connecting peptide, transmembrane and cytoplasmic domains, as well as part of the 3′ UTR, are encoded by the fourth exon and the rest of the 3′ UTR is encoded by the fifth exon. Southern blot analyses using an exon three probe revealed two to four hybridizing fragments with considerable restriction fragment length polymorphisms evident among randomly selected outbred channel catfish. These findings are consistent with the presence of at least two functional polymorphic MHC class II A gene loci. An unusual aspect of the channel catfish MHC class II α chain is its lack of N-linked glycosylation sites.
59 citations
TL;DR: The hypothesis that fish are capable of a genetically restricted specific cell-mediated cytotoxicity is supported, using clonal ginbuna crucian carp leukocytes against allogeneic erythrocytes and effector cells isolated from peripheral blood.
Abstract: Cell-mediated cytotoxicity of clonal ginbuna crucian carp leukocytes against allogeneic erythrocytes is described using a sensitive non-radioactive in vitro assay. Hemoglobin released from target erythrocytes after cell-mediated erythrolysis was detected by tetramethylbenzidine (TMB). TMB assay showed clear correlation with a 51Cr-release assay and even exhibited higher cytotoxicity. The use of erythrocytes as target cells has several advantages over a conventional 51Cr-release assay. Erythrocytes do not have cytotoxic activity, are relatively homogeneous, are available in large numbers and erythrocyte donors need not be killed. Leukocytes from fish sensitized by erythrocyte injection or scale grafting efficiently lysed allogeneic erythrocytes, but did not kill isogeneic or autologous erythrocytes. In contrast, leukocytes from unsensitized fish did not lyse allogeneic erythrocytes and repeated sensitizations by allogeneic grafts were necessary to induce cytotoxic cells. Effector cells isolated from peripheral blood showed a higher cytotoxic effect toward allogeneic target cells than effector cells isolated from kidney. These studies support the hypothesis that fish are capable of a genetically restricted specific cell-mediated cytotoxicity.
52 citations
TL;DR: Fluorescence spectra of the supernatant of adherent haemocyte monolayers from Mytilus galloprovincialis, supplemented with homovanillic acid or with a tyrosyl peptide glycylglycyltyrosine, were recorded before and after stimulation by zymosan, indicating the presence of peroxidases with some properties of myeloperoxidase, in adherence haemocytes from M. gallopovincialis.
Abstract: Fluorescence spectra of the supernatant of adherent haemocyte monolayers from Mytilus galloprovincialis, supplemented with homovanillic acid or with a tyrosyl peptide glycylglycyltyrosine (GGY), were recorded before and after stimulation by zymosan. The formation of fluorescent derivatives was observed to have spectral characteristics similar to those of fluorescent compounds generated by the exposure of homovanillic acid or GGY to a horseradish peroxidase/hydrogen peroxide system in vitro. Lucigenine-enhanced chemiluminescence (CLluc) of M. galloprovincialis haemocytes stimulated by zymosan or by phorbol ester (PMA) was measured in the presence and absence of sodium azide, a peroxidase inhibitor. Sodium azide inhibited the CLluc of haemocytes stimulated by zymosan, an effective stimulus for myeloperoxidase secretion in human polymorphonuclear leukocytes, but not the CLluc of haemocytes stimulated by PMA, indicating the presence of peroxidases with some properties of myeloperoxidase, in adherent haemocytes from M. galloprovincialis.
45 citations
TL;DR: These experiments support the tenet in Buss's hypothesis that germ cell and somatic cell parasitism can occur in fused chimeras and that a somatic appearance may mask the winner of a gametic war.
Abstract: A colonial protochordate, Botryllus schlosseri, undergoes a natural transplantation reaction in the wild that results alternatively in colony fusion (chimera formation) or inflammatory rejection. A single, highly polymorphic histocompatibility locus (called Fu/HC) is responsible for rejection versus fusion. Gonads are seeded and gametogenesis can occur in colonies well after fusion, and involves circulating germ-line progenitors. Buss proposed that colonial organisms might develop self/non-self histocompatibility systems to limit the possibility of interindividual germ cell “parasitism” (GCP) to histocompatible kin [Buss, L. W. (1982) Proc. Natl. Acad. Sci. USA 79, 5337–5341 and Buss, L. W. (1987) The Evolution of Individuality (Princeton Univ. Press, Princeton]. Here we demonstrate in laboratory and field experiments that both somatic cell and (more importantly) germ-line parasitism are a common occurrence in fused chimeras. These experiments support the tenet in Buss’s hypothesis that germ cell and somatic cell parasitism can occur in fused chimeras and that a somatic appearance may mask the winner of a gametic war. They also provide an interesting challenge to develop formulas that describe the inheritance of competing germ lines rather than competing individuals. The fact that fused B. schlosseri have higher rates of GCP than unfused colonies additionally provides a rational explanation for the generation and maintenance of a high degree of Fu/HC polymorphism, largely limiting GCP to sibling offspring.
44 citations
TL;DR: Cross-reactivity of antibodies against bovine, human, ovine and mouse cell surface proteins was tested on beluga whale peripheral blood lymphocytes using flow cytometry and specificity of these antibodies was demonstrated by immunoprecipitation of beluga proteins with similar molecular weight to that of other species.
Abstract: Widespread efforts are currently made to classify morphologically indistin-guishable lymphocyte subpopulations in several species. In order to increase the knowledge in cetacean immunology, cross-reactivity of antibodies against bovine, human, ovine and mouse cell surface proteins was tested on beluga whale ( Delphinapterus leucas ) peripheral blood lymphocytes using flow cytometry. Anti-MHC class I and II as well as anti-CD2 reacted with virtually all peripheral blood lymphocytes. Anti-TCR γδ and anti-CD4 reacted with respectively 31% and 30% of peripheral blood lymphocytes. B lymphocytes were identified by an antisurface IgM which was present on 6% of blood lymphocytes. Specificity of these antibodies was demonstrated by immunoprecipitation of beluga proteins with similar molecular weight to that of other species. These results could be useful for further immunotoxicological evaluation of highly versus mildly contaminated populations of belugas.
TL;DR: The inability of viable L. anguillarum to stimulate hemocyte ROS production, as measured by CL, does not support the proposed role for ROS in hemocyte-mediated bactericidal activity.
Abstract: Luminol- and lucigenin-augmented chemiluminescence (CL) were used to evaluate the ability of Listonella (formerly Vibrio) anguillarum to stimulate the production of reactive oxygen species (ROS) by Crassostrea virginica hemocytes. Whereas heat-killed L. anguillarum stimulated hemocyte CL in the lucigenin system, viable L. anguillarum did not. Neither viable nor heat-killed bacteria stimulated hemocyte production of luminol CL. Metabolically active L. anguillarum generated ROS, as indicated by luminol and lucigenin CL. It is proposed that bacterial catalase suppressed hemocyte-derived luminol CL. L. anguillarum, which possesses the antioxidant enzyme catalase, suppressed luminol CL generated by zymosan-stimulated hemocytes. Conversely, the catalase negative bacterium Carnobacterium piscicola had no effect on hemocyte-derived luminol CL elicited by zymosan. The inability of viable L. anguillarum to stimulate hemocyte ROS production, as measured by CL, does not support the proposed role for ROS in hemocyte-mediated bactericidal activity.
TL;DR: In order to understand the cellular defense system in the giant clam Tridacna crocea, which harbors symbiotic microalga zooxanthella, hemocytes of the Giant clam were characterized using light and electron microscopy using eosinophilic granular hemocytes.
Abstract: In order to understand the cellular defense system in the giant clam Tridacna crocea, which harbors symbiotic microalga zooxanthella, hemocytes of the giant clam were characterized using light and electron microscopy. Three types of hemocytes, which we named eosinophilic granular hemocytes, agranular cells, and morula-like cells, were recognized. The eosinophilic granular hemocyte contained granules approximately 0.6 &mgr;m in diameter. The agranular cell adhered to glass surfaces and contained electron-lucent granules and few electron-dense granules. The morula-like cell was packed with large (approximately 3 &mgr;m in diameter), electron-dense granules. The eosinophilic granular hemocyte was acid phosphatase positive and showed phagocytic ability against latex particles. The agranular cell and the morula-like cell lacked phagocytic ability. When the hemolymph was exposed to seawater, the hemocytes coagulated to make large clots. The agranular cells were mainly found in the core space of the clots. The morula-like cells released the large granules in the aggregation process.
TL;DR: Results suggest that WCL 9 is a specific marker for early thymocytes, together with the absence of WCL9+ cells in other lymphoid organs, strongly suggest thatWCL9 was reactive with 30-50% ofThymocytes and not with lymphoid cells from blood, pronephros, spleen and intestine.
Abstract: A monoclonal antibody against thymocytes (WCL9; of IgG1 class) was produced by immunization of mice with isolated membrane molecules of carp thymocytes. Flow cytometric and fluorescence microscopic analysis showed that WCL9 was reactive with 30–50% of thymocytes and not with lymphoid cells from blood, pronephros, spleen and intestine. Cryo-sections of thymus showed a WCL9+ and WCL9− region in 3-month-old fish and only WCL9+ cells in 1-week-old fish. Because the WCL9− region is more medulla-like, the WCL9+ cells can be considered as cortical thymocytes. The majority of WCL9+ thymocytes appeared to have a higher density (1.06–1.07 g/mL) than the WCL9− cells (1.02–1.06 g/mL). Immunogold labelling or comparison of both density fractions did not show clear ultrastructural differences between WCL9+ and WCL9− thymocytes. The WCL9− fraction could be stimulated much better with PHA than the WCL9+ fraction. Removal of adherent cells or adding adherent accessory cells did not influence this result. Immunochemical analysis showed that WCL9 reacted with a protein determinant present on two molecules (Mr: 200 and 155 kDa) under reduced and non-reduced conditions. These results, together with the absence of WCL9+ cells in other lymphoid organs, strongly suggest that WCL9 is a specific marker for early thymocytes.
TL;DR: The previously established role of Gallysin-1 as an effector protein in the protective response of Galleria mellonella indicates that arylphorins may play a role in insect immune responses.
Abstract: Gallysin-1, an inducible effector protein in the protective response of Galleria mellonella larvae is a 75 kDa component of hemolytically active material (HAM) isolated from immune cell-free hemolymph. The sequence of the first 20 N-terminal amino acids of the antibacterial protein Gallysin-1 is identical to the predicted sequence of the first 20 amino acids of the Galleria arylphorin Lhp76 (larval hemolymph protein 76). A murine monoclonal antibody to the 20 amino acid N-terminal peptide of Gallysin-1 (GYPQYHYDVETRKLDPSLVN) provides additional evidence for a link between Gallysin-1 and Lhp76, and is used to characterize HAM further. HAM, initially characterized as a mixture of two proteins, Gallysin-1 and a 69 kDa component is now identified as a 450-500 kDa heteromultimer, designated Gallysin. In vivo levels of Gallysin rise during the effector phase of an induced immune response. The monoclonal antibody inhibits the hemolytic activity of Gallysin. In addition to a hemolytic activity for mammalian erythrocytes, Gallysin possesses a cytotoxic activity for the human tumor cell line, K562. Lipopolysaccharides (LPS) and a Pseudomonas aeruginosa vaccine induce a cytotoxic activity which reaches its maximum levels in the hemolymph early (2 hours post-vaccination) in the protective response. The partially purified cytotoxic material (Cyt-M) obtained from cell-free hemolymph collected 2 hours after vaccination has hemolytic activity and shows structural similarities to Gallysin and Lhp76. The previously established role of Gallysin-1 as an effector protein in the protective response of Galleria mellonella indicates that arylphorins may play a role in insect immune responses.
TL;DR: Indications for the existence of soluble molecules which are released by the cells and which enhance the LPS-triggered activation are given.
Abstract: The suitability of the hemocyte cell line BTI-EA-1174-A from Estigmene acraea (Lepidoptera) to serve as a tool for studying insect immune reactions in vitro was investigated. Addition of bacterial lipopolysaccharides to the cultures caused enhanced phagocytosis of silica beads, as well as increased lysozyme activity in the cell culture supernatants. Addition of fungal β1,3-glucans did not result in any activation. The LPS-influenced (1 mg/mL) increase of phagocytic reactions against the silica beads was at its highest within 24 h after LPS-addition. Activated cells exhibited drastic changes in their morphology in connection with reduced cell numbers in the cultures but without increased mortality rates. LPS-dosages higher than 10 μg/mL LPS provoked significantly enhanced lysozyme activities. A maximal induction took place with 1 mg/mL LPS. The lysozyme activity started to rise 2 days after LPS-addition, further increase was observed up to the seventh day. The responsible protein was isolated from cell culture supernatants and N-terminally sequenced. The exact molecular mass was determined by mass spectrometry as 14.080 kDa. The amino acid sequence of the analysed portion revealed high sequence-similarity to the lysozymes of other lepidopteran insects as well as to hen egg lysozyme. Further results presented in this paper give indications for the existence of soluble molecules which are released by the cells and which enhance the LPS-triggered activation.
TL;DR: These mAbs effectively blocked the mixed lymphocyte reaction and the proliferative response to viral antigens (African swine fever virus and to staphylococcal enterotoxin B) and can be useful reagents for studying MHC class II molecules of pig and crossreactive species, and the immunological processes where they are involved.
Abstract: A set of five monoclonal antibodies (mAb) against porcine major histocompatibility complex (MHC), or swine leukocyte antigens (SLA), class II molecules has been characterized These mAbs appear to recognize monomorphic determinants on SLA-DR (2F4, 1F12 and 2E9/13) and SLA-DQ (BL2H5 and BL4H2) molecules, as assessed by flow cytometry and immunoprecipitation By Western blot, the 2F4, 1F12, BL2H5 and BL4H2 epitopes were located on the beta-chains of these molecules mAbs 2F4 and 1F12 crossreact with leucocytes of dog, cattle, horse and human; mAbs 2E9/13, BL2H5 and BL4H2 bind leucocytes of cattle but not those of human, dog and horse These mAbs effectively blocked the mixed lymphocyte reaction and the proliferative response to viral antigens (African swine fever virus) and to staphylococcal enterotoxin B Therefore, these mAbs can be useful reagents for studying MHC class II molecules of pig and crossreactive species, and the immunological processes where they are involved
TL;DR: The presence, in sipunculan coelomocytes, of antigens cross-reactive with CD14, the alpha chain of CR3 and of p150,95 raises the possibility that molecules related, although not necessary homologous, to the mammalian counterparts may have a role in the defense systems of these animals.
Abstract: Coelomocytes of Themiste petricola , a marine invertebrate of the phylum Sipuncula, were exposed in vitro to bacterial lipopolysaccharides (LPS), and the phagocytic activity against heat-killed yeast ( Saccharomices cerevisiae ) was evaluated using a flow cytometric assay. An increase of phagocytic activity was observed following pre-incubation of coelomocytes over 20 h with either 5 μg/mL LPS or 1.5 μg/mL phorbol 12-myristate 13-acetate (PMA). The phagocytic enhancement induced by LPS was blocked by co-incubation with polymixin B, a ligand for the lipid A region of LPS. In a 72 h stimulation assay, LPS was also found to enhance phagocytosis. The enhancement was significantly higher when coelomocytes were incubated with LPS plus coelomic plasma. Using mAbs directed against human CD14 and components of the human LFA-1 complex, we identified coelomocyte surface antigens cross-reactive with CD14, CD11b and CD11c. The expression of CD11b and CD11c antigens was augmented by LPS treatment of coelomocytes. By double fluorescence assays, using mAb Leu-M3 and fluorescein labeled yeast, phagocytic coelomocytes were found to be mainly anti-CD14 positive. No cross-reactions were detected with mAbs against CD11a and CD18. Enzymatic treatment of coelomocytes with phosphatidyl inositol phospholipase C (PI-PLC) reduced the expression of the CD14-like antigen. The presence, in sipunculan coelomocytes, of antigens cross-reactive with CD14, the α chain of CR3 and of p150,95 raises the possibility that molecules related, although not necessary homologous, to the mammalian counterparts may have a role in the defense systems of these animals.
TL;DR: It is proposed that, by late life, the T cell compartment in late life may be more prone to immune deficiency or cytokine-mediated dysregulation in response to new or previously encountered pathogens.
Abstract: Elderly humans are at significant risk with regard to the incidence and severity of many infectious diseases and cancers. Current theory holds that these late-life vulnerabilities arise, in part, through age-related changes in immune function, particularly in the T lymphocyte lineage. Herein, we discuss how such factors as thymic involution and ongoing T cell differentiation in the peripheral tissues contribute to progressive and irreversible shifts in the state of differentiation of the mature T cell pool. We propose that, by late life, these processes yield a T cell compartment with a suboptimal balance of naive and memory T cell subsets, each with altered, subset-specific programs for cytokine gene expression. As such, the T cell compartment in late life may be more prone to immune deficiency or cytokine-mediated dysregulation in response to new or previously encountered pathogens.
TL;DR: Age-related alterations in sympathetic noradrenergic innervation in primary and secondary lymphoid organs from mouse and rat occur concurrently with age-associated changes in immune function, contributing to a greater understanding of sympathetic nervous system regulation of immune function.
Abstract: We have examined age-related alterations in sympathetic noradrenergic (NA) innervation in primary and secondary lymphoid organs from mouse and rat. As the thymus involuted with age, the density of NA innervation and norepinephrine (NE) concentration increased markedly. Total thymic NE was not altered significantly with age, suggesting that NA innervation is maintained as the thymus involutes. In the rat spleen, NA innervation and NE concentration were diminished with age. Enhanced antibody responses and in vitro proliferation to a T-dependent protein antigen were observed following selective destruction of NA nerve fibers with the neurotoxin 6-hydroxydopamine (6-OHDA), demonstrating that the diminished NA innervation in the aged spleen is capable of signaling the immune system. Plasticity of NA nerves in old rats was demonstrated following lesioning with 6-OHDA and in intact rats treated with L-deprenyl, a monoamine oxidase B inhibitor. These age-related alterations in NA innervation of lymphoid organs occur concurrently with age-associated changes in immune function. Understanding the functional relationship between these two physiological systems in aging will contribute to a greater understanding of sympathetic nervous system regulation of immune function.
TL;DR: It is established that the addition of homologous red blood cells enhances the in vitro proliferative responses of duck T lymphocytes, especially when limiting doses of PHA and ConA are used.
Abstract: The in vitro proliferative responses of duck PBMCs purified from Ficoll-Paque density gradients to the mitogens PHA and ConA show a great deal of duck-to-duck variation. Better responses were consistently obtained by using nylon wool fractionation to increase the proportion of duck T lymphocytes in PBMC preparations and then culturing these preparations with homologous monocytes, purified from PBMC preparations by their adherence properties. We have also established that the addition of homologous red blood cells enhances the in vitro proliferative responses of duck T lymphocytes, especially when limiting doses of PHA and ConA are used. Duck T lymphocytes showed greater and more consistent proliferation when cultures were incubated at 37 degrees C as compared to incubation at 41.6 degrees C. The improved consistency of higher proliferative responses with this assay should make it more suitable for detecting in vitro proliferative responses of antigen-specific T lymphocytes, as a measure of in vivo induced cell mediated immune responses.
TL;DR: There are two different modes of defensive response involving cuticle formation in A. yamazii, and one or other of the modes should be elicited in response to many damaging stimuli.
Abstract: The defensive responses in ascidian tunic were investigated in a colonial ascidian Aplidium yamazii by means of light- and electron-microscopy with special reference to the cuticle formation (restoration) of the tunic. When the tunic was wounded by cutting with a razor blade, the tunic around the wounds shrank to close the wound, and electron-dense fibers appeared and covered the exposed surface of the wound. The tunic shrinkage is probably promoted by the contraction of the cellular network in the tunic. On the other hand, when a part of the tunic was damaged by the injection of distilled water or 5% NaOH, a cuticular boundary appeared in the tunic, separating the damaged and undamaged tunic. Before the completion of the boundary formation, tunic cells gather around the boundary precursor that is formed from the electron-dense fibers. Thus, there are two different modes of defensive response involving cuticle formation in A. yamazii. Although the regulatory mechanism is still uncertain, one or other of the modes should be elicited in response to many damaging stimuli.
TL;DR: Cytotoxicity was significantly greater in tumor homogenate injected animals that resisted tumor development for more than 5 months as compared to those that developed tumors quickly, which implies that the cytotoxic effector is directed towards retrovirus infected cells.
Abstract: Lymphocytes from tumor-bearing damselfish are cytotoxic towards target cell lines derived from damselfish neurofibromatosis. These cell lines contain at least one retrovirus which appears to be related to the etiology of the disease. The current studies were designed to characterize the effectors of this cytotoxic reaction. Data presented here show that cells separated using an antibody (5C6.10.4) directed towards non-specific cytotoxic cells of catfish sequesters all antitumor activity in the 5C6.10.4 negative population. Thus, damselfish 5C6.10.4 positive cells bind to tumor targets, but do not contribute to target cell death. In contrast, SC6.10.4 positive cells are cytotoxic towards xenogeneic erythrocytes. Cytotoxicity of splenocytes from animals inoculated with virus purified from the 88–503 cell line suggested that prior exposure to the retrovirus enhanced reactivity, especially towards 88–503. In addition, cytotoxicity was significantly greater in tumor homogenate injected animals that resisted tumor development for more than 5 months as compared to those that developed tumors quickly. Lastly, cytotoxic responsiveness towards primary cultures of mock and virus infected autologous and allogeneic cells implies that the cytotoxic effector is directed towards retrovirus infected cells.
TL;DR: In intestine-derived cells with characteristics of early-stage T cell precursors were studied for their ability to regenerate IEL T cell populations following transfer into irradiated recipient mice, providing evidence that T cell progenitors located in the intestinal mucosa are the likely source of most intestinal IELs.
Abstract: Lymphocytes in the murine small intestine epithelium are known to have a high proportion of extrathymic T cells. To explore the possibility that small intestine intraepithelial lymphocytes (IELs) are derived from T cell progenitors present within the intestine, intestine-derived cells with characteristics of early-stage T cell precursors were studied for their ability to regenerate IEL T cell populations following transfer into irradiated recipient mice. Cells within this population lacked markers of mature T cells but expressed heat-stable antigen, the c-kit receptor for stem cell factor, and/or the pre-T cell alpha gene. Upon adoptive transfer, donor cells preferentially homed to the intestine and did not repopulate the thymus or extraintestinal peripheral lymphoid tissues. IELs derived from the donor precursor pool included both (alpha beta and gamma delta T subsets and consisted of phenotypically heterogeneous cell populations defined by CD4 and CD8. These findings provide evidence that T cell progenitors located in the intestinal mucosa are the likely source of most intestinal IELs.
TL;DR: It appeared that CD 4 T cells from PP mature faster than SP CD4 T cells, and they are not subject to the deleterious effect of aging.
Abstract: The purpose of this study was to investigate in rats, by double-label immunofluorescence and flow cytometric analysis, the age related changes in the CD4 subset of gut-associated lymphoid tissues and spleen. We found that the percentage of CD4 + T cells in Peyer's patches (PP) and spleen (SP) increased during the first 6 weeks after weaning. An age-related decrease of the CD4 subset was observed in SP of aged rats, but not in their PP. In all lymphoid tissues studied, an age-related decrease of the Thy-1 + subset was observed from weaning to 2 years of age. Analysis of the naive CD4 subset (CD45RC +) showed that in SP this subset increased during the first 9 weeks of age, and declined in aged rats. However, in PP this subset presented a slow decrease from weaning until 2 years of age. Together with the decrease of the naive subset, a sharp increase of the memory/activated CD4 + cells (CD45RC — Thy-1 —) was observed in PP, and to a lesser extent in SP. When the maturation of the CD4 T cells in PP was followed during the first week after weaning, we found that an important proportion of this subset changes its phenotype at this time, from recent thymic emigrant (CD45RC − Thy-1 +) to naive T cell (CD45RC +Thy-1 −) and then to activated/memory cell (CD45RC — Thy-1 —). Therefore it appeared that CD4 T cells from PP mature faster than SP CD4 T cells, and they are not subject to the deleterious effect of aging. One surprising point was the different kinetics of the CD4 T cells observed in mesenteric lymph nodes (MLN). No age-related changes were observed in the CD4 subset at this site. Furthermore, the percentage of the CD45RC + cells did not decrease in aged rats, and in the first 9 weeks of life an increase of this subset was observed.
TL;DR: Investigations on the protective efficacy of influenza vaccination in the elderly have demonstrated a clinical protection of > or = 50% for preventing hospitalization and live attenuated influenza vaccine conferred protection similar to that obtained with a conventional subunit vaccine.
Abstract: Influenza vaccination of elderly people has been shown to be useful. All vaccine types are well tolerated by higher age group vaccinees. Actually, whole virus vaccine, split virus vaccine and subunit vaccine are used in the vaccination of the elderly. Some studies have suggested that the induction of serum influenza antibody production was reduced in elderly persons when compared with that elicited in younger persons. However, investigations on the protective efficacy of influenza vaccination in the elderly have demonstrated a clinical protection of ⩾ 50% for preventing hospitalization. Live attenuated influenza vaccine conferred protection similar to that obtained with a conventional subunit vaccine. A virosomal unilamellar trivalent hemagglutinin vaccine showed promising serological results compared with those obtained with a whole cell vaccine and with a subunit vaccine, respectively. The actual policy is to vaccinate persons ⩾ 65 years of age and the groups that can transmit influenza to them. Each year's vaccine should contain three virus strains representing the influenza viruses that are likely to circulate in the upcoming winter.
TL;DR: The data suggest that restoration of the T-cell immune function in aged individuals must be carried out in concert with correction of other immune factors that down modulate the acute-phase response to prevent undesirable side-effects.
Abstract: Two prominent features associated with immunosenescence are thymic involution and altered T-cell phenotype and responsiveness. We have shown previously that in CD2-fas transgenic mice, in which the Fas apoptosis molecule is constituatively expressed on T cells, T-cell senescence is greatly reduced. Using a different experimental approach, the relationship between T-cell senescence and apoptosis was analyzed on human PBMCs. The results indicate that there was increased apoptosis of CD45RO− (CD45RA+) T cells upon activation. We propose that this could account for the increase in CD45RO+ ‘memory’ T cells with aging in humans. Together these results are consistent with the notion that T-cell senescence is associated with altered apoptosis and decreased T-cell responsiveness. T-cell responsiveness remained high in CD2-fas transgenic aged mice, but there was no increase in overall life span of the mice. Increased T-cell responsiveness was associated with an increased acute-phase response and amyloid A deposition in the glomerulus of these mice. These data suggest that restoration of the T-cell immune function in aged individuals must be carried out in concert with correction of other immune factors that down modulate the acute-phase response to prevent undesirable side-effects.